1. Technical Field
This invention relates to a system for outputting speech. The system includes methods and apparatuses for outputting speech, methods for updating speech, and a data carrier including speech data.
2. Related Art
When interfacing with a user, various applications increasingly use speech output. For example, speech output may be used when the attention of a user, particularly the visual attention, should not be distracted by an optical interface. A typical example of an application that should not distract the user is a car navigation system, which directs the driver to a predetermined target. While driving, the driver should carefully watch the traffic situation around him, rather than a visual interface from a car navigation system. Thus, speech output as an acoustical interface is desirable in this situation.
A conventional method of providing speech output as an interface between an application and a user may be explained with reference to FIG. 7. While performing its main task, an application may come to a point where a certain output to a user is desired. For example, during startup a car navigation system may determine that a required data CD (including, for example, navigation data) is missing. Thus it may be desirable for the navigation system to output a message conveying that the data CD should be inserted. Modern systems for speech output generally provide a list of speech segments (which may be thought of as sound files) that may be strung together in various ways to form various messages. These speech segments may be of any size depending on criteria such as: data quantity, software complexity, speech driver complexity and the like.
FIG. 7 shows a table 70 including speech segments in the right-hand column and segment designators in the left-hand column. Each segment designator identifies a particular speech segment. In order to create a desired output speech, an application, such as a navigation system, would need to have knowledge of the contents of the table 70. Assuming such knowledge, the application would produce a sequence of segment designators, and take from the table 70, the respective speech segments to compose the desired speech output. For example, the navigation system or a speech driver of the navigation system may compose the designator sequence INST NAVCD. This would reference the two speech segments “Please insert” and “navigation CD” in table 70, thus creating the sentence “Please insert navigation CD.” In another example, the navigation system might determine that the driver needs to turn left at the next side street in order to reach his destination. The navigation system or its speech driver may, for example, output the sequence of designators PLSE TURN LFT AT NEXT SIDS. This would reference the respective speech segments in table 70 to create the sentence “Please turn left at the next side street.” Generally, the data in table 70 is usually provided together with the application program and/or together with application-related data such as, navigation data.